Peritoneal Encapsulation with Incarcerated Meckel Diverticulum Contributing to Small Bowel Obstruction

Ochsner Journal Publish Ahead of Print, published on November 28, 2018 as doi:10.31486/toj.17.0114 CASE REPORT

Ochsner Journal XX:1–3, 2019 © Academic Division of Ochsner Clinic Foundation DOI: 10.31486/toj.17.0114

Peritoneal Encapsulation With Incarcerated Meckel Diverticulum Contributing to Small Bowel Obstruction

Keenan J. Robbins, BS,1 Hannah Z. Kooperkamp, MD,2 Ralph L. Corsetti, MD1,2

1The University of Queensland School of Medicine, Ochsner Clinical School, New Orleans, LA 2Department of Surgery, Ochsner Clinic Foundation, New Orleans, LA

Background: Meckel diverticulum is the most common congenital gastrointestinal malformation, but it is rarely symptomatic. Peritoneal encapsulation is a rare abnormality of embryonic development and may present with obstruction, although it too is usually asymptomatic. Case Report: We report the case of an 82-year-old male who presented with symptoms and imaging findings consistent with small bowel obstruction. During laparotomy, a peritoneal encapsulation was observed containing the majority of the small bowel. A Meckel diverticulum was discovered tethered to the small bowel mesentery by a mesodiverticular band, preventing egress from the accessory peritoneal membrane and appearing to be the cause of the obstruction. Conclusion: This patient had 3 rare findings—peritoneal encapsulation, Meckel diverticulum, and a mesodiverticular band— contributing to cause an acute small bowel obstruction. The presence of all of these features in one patient is extremely rare, and we believe this is the first description of such a phenomenon.

Keywords: Hernia–abdominal, intestinal obstruction, Meckel diverticulum

Address correspondence to Ralph L. Corsetti, MD, Department of Surgery, Ochsner Clinic Foundation, 1514 Jefferson Hwy., New Orleans, LA 70121. Tel: (504) 842-2444. Email: [email protected]

INTRODUCTION CASE REPORT A Meckel diverticulum is a vestige of the fetal omphalome- An 82-year-old male presented to the emergency depart- senteric duct and is the most common congenital gastroin- ment with 24 hours of diffuse abdominal pain accompanied testinal (GI) malformation. It is thought to occur in 2%-4% by nausea and anorexia. His last bowel movement was the of the population1 and is rarely symptomatic. Most cases afternoon of presentation. His medical history was significant of symptomatic Meckel diverticula occur in children, and for 2 episodes of painless rectal bleeding more than 15 GI bleeding is the most common manifestation.2 Bleeding years prior that were attributed to diverticulitis at the time. can also occur in adults, but the most common presentation The patient also reported a postoperative ileus after a bilater- is obstruction, followed by ulceration, diverticulitis, or perfo- al total knee arthroplasty in 2003. He had no history of ab- ration.3 Preoperative diagnosis of a Meckel diverticulum is dominal operations. While his last colonoscopy had been difficult, and its existence is usually discovered incidentally performed more than 10 years prior, the patient had no his- during surgery for another indication.4 tory of abnormal colonoscopies. He was afebrile and had a Peritoneal encapsulation is an exceptionally rare phenom- blood pressure of 174/78 mmHg, but vital signs were other- enon in which an anomaly during the physiologic midgut wise normal. His examination was remarkable for a firm, dis- herniation stage of embryonic development results in an ac- tended abdomen that was diffusely tender to palpation with cessory peritoneal membrane surrounding some or all of the focally increased tenderness in the left upper and lower small bowel.5 Although usually asymptomatic, peritoneal en- quadrants. No rigidity, rebound tenderness, or appreciable capsulation can present with recurrent episodes of colicky masses were noted. An easily reducible incidental umbilical abdominal pain or acute small bowel obstruction. Like a hernia was noted that had not bothered the patient. Com- Meckel diverticulum, peritoneal encapsulation is difficult to puted tomography (CT) showed dilation of the majority of appreciate on imaging and is most often diagnosed unex- the small bowel and decompressed terminal ileum without pectedly in the operating room. an identifiable transition point. The scan showed scattered We report what we believe to be the first documented case diverticula but no evidence of diverticulosis. of a Meckel diverticulum incarcerated within a peritoneal en- Given the patient’s age and absence of prior abdomi- capsulation and causing acute small bowel obstruction. nal surgeries, the presentation and imaging findings were

Figure 3. Computed tomography shows the small bowel abnormally localized in the upper left portion of the abdomen. An appreciable thin membrane, denoted by an arrow, surrounds the small bowel, representing the peritoneal encapsulation.

Figure 1. A thin, translucent membrane encased the small bowel from the ligament of Treitz to the terminal ileum. French nasogastric tube in the process. Near the terminal ileum was a clear transition point with dilated proximal bowel and normal bowel distally. On the antimesenteric concerning for an internal hernia or malignancy as the un- side of this transition point, we discovered a Meckel divertic- derlying etiology of the small bowel obstruction. The pa- ulum, measuring 3.1 × 2.2 cm (Figure 2). The distal aspect of tient was taken to the operating room for an exploratory the diverticulum was tethered into the small bowel mesen- laparotomy. tery via a mesodiverticular band, potentially serving as a Inspection of the peritoneal cavity showed no evidence of point of fixation leading to kinking of the bowel or preventing intestinal malrotation, carcinomatosis, or infection. However, egress from the peritoneal encapsulation. Upon palpation, a large, well-vascularized, thin, translucent membrane en- the Meckel diverticulum was noted to be abnormally thick- cased the small bowel from the ligament of Treitz to the ter- ened, possibly consistent with ectopic gastric or pancreatic minal ileum (Figure 1). The membrane was incised, with a mucosa in the lumen of the diverticulum. The pathology re- segment resected and sent to pathology despite its overall port did not mention the presence of ectopic tissue but benign appearance. The bowel was then run from the ligament of Treitz distally, decompressing the bowel via an 18

Figure 4. The distal ileum makes a sharp turn, and an appre- Figure 2. A Meckel diverticulum was observed in the distal ciable transition point is at what appears to be the point of ileum. The apex of the diverticulum was tethered to the egress from the accessory peritoneal membrane. The de- small bowel mesentery by a mesodiverticular band. compressed distal bowel is indicated by an arrow.

2 Ochsner Journal Robbins, KJ noted ischemic and reactive mucosal changes. Because we was likely an interdependent pathology. Since the first de- thought the Meckel diverticulum contributed to the obstruc- scription of peritoneal encapsulation in 1868, only 30 in- tive process and because of diverticular wall thickening in stances have been reported in the medical literature.8 As the setting of a history of GI bleeding, we elected to resect none of the reported cases we had access to described the diverticulum. Short margins of ileum on either side peritoneal encapsulation with an associated Meckel di- of the diverticulum were included in the resection, and the verticulum causing acute small bowel obstruction, we be- bowel was reanastomosed using a stapled side-to-side tech- lieve this case report to be the first description of this nique. The bowel was then returned to the abdomen, the in- phenomenon. cidental umbilical hernia was repaired, the fascia was closed with running looped #1 PDS suture, and the subcutaneous CONCLUSION tissue was irrigated thoroughly before skin closure with The infrequency of symptomatic peritoneal encapsulation staples. is such that it will likely continue to be an incidental finding Bowel function returned on postoperative day 4, the pa- during laparotomy under the presumption of other more ’ tient s diet was advanced, and he was discharged home common causes of acute abdomen. on postoperative day 8. The patient attended all follow-up appointments, and his convalescence had no significant de- ACKNOWLEDGMENTS viations from the normal course. He continues to do well The authors have no financial or proprietary interest in the without recurrence of symptoms. subject matter of this article. DISCUSSION REFERENCES Isolated case reports have suggested the inclusion of peri- 1. Elsayes KM, Menias CO, Harvin HJ, Francis IR. Imaging toneal encapsulation in the differential for acute bowel ob- manifestations of Meckel’s diverticulum. AJR Am J Roentgenol. struction in patients without a history of abdominal 6 2007 Jul;189(1):81-88. surgery. Other case reports have suggested characteristic 2. Park JJ, Wolff BG, Tollefson MK, Walsh EE, Larson DR. Meckel imaging findings to aid in preoperative identification of this 7 diverticulum: the Mayo Clinic experience with 1476 patients anomaly. Reviewing the CT with the benefit of hindsight, (1950-2002). Ann Surg. 2005 Mar;241(3):529-533. an appreciable thin membrane does appear to surround 3. Sagar J, Kumar V, Shah DK. Meckel’s diverticulum: a systematic an unusually localized collection of small bowel (Figure 3). review. J R Soc Med. 2006 Oct;99(10):501-505. This finding was commented upon preoperatively, but the 4. Sharples AJ. Meckel diverticulum causing small bowel significance was unclear. The collection of bowel appears obstruction. BMJ Case Rep. 2010;2010. doi: 10.1136/ to displace the middle colic vein, forcing it into an unusually bcr.06.2009.1970. tortuous course. A clearly demarcated plane between the 5. Naraynsingh V, Maharaj D, Singh M, Ramdass MJ. Peritoneal collection of bowel and adjacent colon and other structures encapsulation: a preoperative diagnosis is possible. Postgrad is suggestive of the small bowel residing in an accessory Med J. 2001 Nov;77(913):725-726. sac. At what appears to be the point of egress from this 6. Griffith D, Boal M, Rogers T. Peritoneal encapsulation; a rare sac, the ileum turns abruptly and is decompressed distally cause of bowel obstruction. Ann R Coll Surg Engl. 2017 Jan;99 (Figure 4). This area may represent the point of obstruction (1):e11-e12. doi: 10.1308/rcsann.2016.0264. and corresponds with where we discovered the Meckel di- 7. Casas JD, Mariscal A, Martínez N. Peritoneal encapsulation: verticulum intraoperatively. CT appearance. AJR Am J Roentgenol. 1998 Oct;171(4):1017- The rarity of peritoneal encapsulation, the rarity of Meckel 1019. diverticulum, and the typically quiescent existence of both 8. Arumugam PK, Dalal AK. Peritoneal encapsulation – an entities make it extremely unlikely for both to not only be unexpected cause of acute intestinal obstruction. J Visc Surg. present in the same individual but to contribute to what 2017 Sep;154(4):303-305. doi: 10.1016/j.jviscsurg.2017.06.001.

This article meets the Accreditation Council for Graduate Medical Education and the American Board of Medical Specialties Maintenance of Certification competencies for Patient Care and Medical Knowledge.

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